1. Field of the Invention
The present invention relates to an electrical control module for a current-limiting fuse and, more specifically, to a module containing electrical components which constitute a detecting and triggering circuit for a high-voltage current-limiting fuse. The module of the present invention is usable in the high-voltage current-limiting fuses described and clamined in commonly assigned U.S. Pat. No. 4,342,978, issued Aug. 3, 1982 in the name of Meister, and in the following commonly-assigned U.S. patent applications: Ser. No. 194,712, filed Oct. 6, 1980, now U.S. Pat. No. 4,359,708 in the names of Jarosz and Panas, Ser. No. 188,660, filed Sept. 19, 1980, now U.S. Pat. No. 4,370,531 in the name of Tobin; Ser. No. 179,367, filed Aug. 18, 1980, and Ser. No. 181,603, filed Aug. 27, 1980, both in the names of Jarosz and Panas; Ser. No. 179,336 filed Aug. 18, 1980 in the name of O'Leary; and Ser. No. 437,925 filed Nov. 1, 1982, and Ser. No. 437,926 filed Nov. 1, 1982, both in the names of Jarosz and Panas.
2. Brief Discussion of the Prior Art
The above-noted commonly assigned patent and patent applications relate to a high-voltage current-limiting fuse which comprises an interrupting module and an control module. The interrupting module comprises a switch section and a fuse section. The switch section has a pair of contacts which are movable relatively apart along a fixed line of direction. In preferred embodiments, one contact is stationary, while the other is movable. The contacts are normally electrically interconnected, resulting in the switch section being closed. A fusible element of the fuse section is in electrical shunt with the contacts of the switch section. When the switch section is closed, a majority of current in a high-voltage circuit to which the fuse is connected for protection thereof flows through the switch section and not through the fusible element. When the switch section is opened, the contacts separate, commutating current formerly flowing therethrough to the fusible element for interruption thereof. Opening of the switch section is achieved by the ignition of a power cartridge located in a cavity defined, in part, by the stationary contact and, in part, by a trailer or piston carried by the movable contact. When the power cartridge ignites, the pressure in the chamber rapidly increases, acting against the trailer to move it and the movable contact away from the stationary contact, to open the switch section.
As generally described in the above patent and patent applications, the ignition of the power cartridge occurs in response to a fault current or other overcurrent in the protected high-voltage circuit to which the fuse is connected. As generally described in the above patent and patent applications, the sensing of fault currents or other over-currents in the protected circuit is achieved by a detecting and triggering circuit which ignites the power cartridge when a fault current occurs.
Since the interrupting module includes a "one-shot" power cartridge, as well as a consumable fusible element, both of which must be replaced following operation of the fuse, a determination has been made that the switch section and the fusible element of the fuse section, which together constitute the interrupting module, should be maintained in a single housing and comprise the single, replaceable interrupting module. Further, since the detecting and triggering circuit is reusable, and normally is not adversely effected by the occurrence of a fault current or other overcurrent in the protected circuit nor by the operation of the interrupting module, it has been determined that the sensing and triggering circuit should be in its own separate, reusable electrical control module.
Accordingly, the present invention relates to the separate electrical control module which contains the detecting and triggering circuit usable with the above-described current-limiting fuse, which module embodies convenient, low cost assembly and may be conveniently associated with the interrupting module so that the two modules may be conveniently connected to a protected circuit for protection against fault currents or over-currents.